Dielectric composition



Aug. 3, 1937. w. DUBlLll-:R

DIELECTRIC COMPOSITION n Filed Aug.. 7, 1954 4o 5o 6o 9a NITRoBENzoL Y voLuMe f INvNoR wsLvuAM Duerme -BY ATTORNEY Patented Aug. 1931 mnmcrnlc conirosrrroN William Dublller; lNew Rochelle, VN. vY., assignor to Cornell-Dubilier Corporation, New York,

., a corporation of New York Application suma 1, 1934, sean No. 'isssss In Germany August 8, 1933 4 (ci. ass- 1) This invention relates to insulating .and dielectric materials, more particularly to a dielectric and/or impregnating liquid for electrical condensers or similar electric devices.-

In electrical condensers employing oil. or wax,

such as paraiiln either rdirectly as a dielectric for the condenser or in which these compounds arel used as an impregnating means. of the ilbrous layers separating the metallic condenser armatures, the capacity of the condenser is determined by the dielectric constant o! the oil or wax' used. By using a compound known under the trade-name o! Halowax", the capacity may be increased als compared to ordinary oil or paramn wax. There is however the disadvantage that not without well-known disadvantages when used in electric condenserswhich are well known in the art.

' 0n the other hand. condensers employing -emc'ient cconstan the condenser oil tight. It'is anwobiect of vide a new insulating or dielectric material for electrical condensers or similar electric devices which isdevoid of the above disadvantages.v

that the use of nitrobenzol a dielectric or impregnatih so liquid. However, for ce practical uses the leakage resistance is sufficiently high to enable "Halowax is expensive and insulating oil which has a disimilar the present invention to pro-- ohms while when using the above mixture benzol in which the leakage resistance is increased as compared to a condenser employing pure nitrobenzol to adapt the condenser i'or useI wheredecreased losses are required.

InV accordance with the invention, there` is 5 'ad ed to the nitrobenzol a suitable compound adaptedto increase theleakage resistance, either in the form oi a .pure mixture and/or ychemical combination. `Il: has been found that chlorinated diphenyl is especially suited for Thus, for insta ce, by using a mlxtureof nitrobenzol an 50% chlorinated diphenyl, a capacity increase of 2.6 times as compared to an equivalent condenser using ordinary oil and in addition a considerable increase ci the leakage 15 resistance as compared to a condenser using pure nitrobenzol is obtained. In a practical example, the leakageresistance in a condenser. unit impregnated with nitrobenzol was about 100 megthe 20 resistance was increased to about 300 megohms. The chart on the accompanying drawing is further explanatory of the novel results according to the'lnvention. It illustrates the variation oi' the capacity and\the resistance of the con- 25 ydenser with varying'ratiosof ,the constituents of the dielectric and/or impregnating mixture, in the example shown consisting of nitrobenzoland chlorinated diphenyl. 'I'he capacities, are shown in microi'arads and the resistance in megohms 30 Aper microfarad and are related to af'standard condenser unit of one microfarad impregnated with ordinary oil or paraflln. As is seen. the capacity oi the condenser using f nitrobenzol mixed' with chlorinated diphenylis- 35 not as high as in'the case where pure nitrobenzo'l is The values obtained however when employing the mixtureare stilll high enough toenable amanufactre of a condenser with tui-elo! the condenser.

By using dierent mlxing'ratios of the nitro'- benzol and chlorinated diphenyl it 'isteasily lliossible. in accordance vwith condenser, to either increase the capacity at the expense ofthe resistance or vice versa. `for instance, as seen from the drawing, -using a mixture chlorinated diphenyl,

,-30% ay somewhat increased this purpose. 10

thedesireduseoi'the504 capacity and considerably decreased resistance is obtained as compared to a condenser with a 50-50 mixture. y

In accordance with a further feature of the 'invention itis furthermore possible to add a different substance to the nitrobenzol or mixture of nitrobenzol and chlorinated diphenyl having similar properties to chlorinated diphenyl for decreasing the resistance o! thecondenser, such as a suitable oil or similar material.

While a specic example of an impregnating mixture fonelectric condensers or similar devices has been given,

it is understood that variations may be made comin: within the broader scope o! moeaeos 

